Changes in the structure of intestinal mucosal flora in colorectal cancer patients / 南方医科大学学报

OBJECTIVE@#To investigate the changes in bacterial flora in fecal samples, at the tumor loci and in adjacent mucosa in patients with colorectal cancer (CRC).@*METHODS@#We collected fecal samples from 13 patients with CRC and 20 healthy individuals and tumor and adjacent mucosa samples from 6 CRC patients. The differences in bacterial composition between the fecal and mucosa samples were analyzed with 16S rDNA sequencing and bioinformatics methods. We also detected the total number of bacteria in the feces using flow cytometry, isolated and identified the microorganisms in the fecal and mucosa samples using common bacterial culture media. We further tested the effects of 7 isolated bacterial strains on apoptosis of 3 CRC cell lines using lactate dehydrogenase detection kit.@*RESULTS@#The bacterial α-diversity in the feces of healthy individuals and in adjacent mucosa of CRC patients was significantly higher than that in the feces and tumor mucosa in CRC patients (P < 0.05). Lactobacillaceae is a specific bacteria in the feces, while Escherichia, Enterococcus, and Fusobacterium are specific bacteria in tumor mucosa of CRC patients as compared with healthy individuals. Cell experiment with3 CRC cell lines showed that Bacteroides fragilis isolated from the tumor mucosa of CRC patients produced significant inhibitory effects on cell proliferation (P < 0.0001), while the isolated strain Fusobacterium nucleatum obviously promoted the proliferation of the cell lines (P < 0.001).@*CONCLUSION@#The bacterial flora in the feces, tumor mucosa and adjacent mucosa of CRC patients is significantly different from that in the feces of healthy individuals, and the fecal flora of CRC patients can not represent the specific flora of the tumor mucosa. Inhibition of F. nucleatum colonization in the tumor mucosa and promoting B. fragilis colonization may prove beneficial for CRC treatment.

Effect and mechanism of aspirin combined with vinorelbine on non-small cell lung cancer / 中国中药杂志

The study aimed to investigate the effect and mechanism of aspirin combined with vinorelbine on the proliferation and apoptosis of non-small cell lung cancer cells. 3-(4-dimethylthiazolyl-2)-2-diphenyltetrazolium bromide(MTT) was used to detect the cytotoxic effect of aspirin and vinorelbine on H460 and A549 cells, and half of inhibitory concentration(IC_(50)) value of drugs as well as synergistic effect were calculated. The results showed that both aspirin and vinorelbine inhibited the cancer cells proliferation by a concentration-dependent manner with IC_(50 )values of 1.553 mmol·L~(-1) and 0.033 μmol·L~(-1) in H460 cells, respectively. The IC_(50 )values of aspirin and vinorelbine were 1.70 mmol·L~(-1)and more than 20 μmol·L~(-1) in A549 cells. The combination index(CI) value was used to evaluate the combined effect of two drugs. Aspirin combined with vinorelbine had synergistic effects at the ratio of 100∶1 on H460 cells and 1∶10 on A549 cells(CI<1). Clone formation and 4',6-diamidino-2-phenylindole(DAPI)/propidium iodide(PI) staining assays were used to verify the effect of the combination of two drugs on proliferation of H460 cells. Compared with the aspirin single group, the combination group had stronger inhibitory effect on the proliferation of H460 cells and the clone formation rate was 49.5%(P<0.05). Furthermore, apoptosis, mitochondrial membrane potential, reactive oxygen species and Western blot experiments were used to explore the synergistic mechanism of aspirin combined with vinorelbine in inhibiting cell proliferation. The results showed that the cancer cell apoptosis rate was 52.8%, the mitochondrial membrane potential was decreased to 33.1%, and the levels of reactive oxygen species was increased to 73.3% in combination group, which were significantly different from those of the single drug treatment groups(P<0.05). Western blot showed that combination group significantly up-regulated the expressions of Bax, p53, cleaved caspase-3 and cytochrome C, while down-regulated the expression of anti-apoptosis proteins such as Bcl-xL and Bcl-2 when compared with single groups. Our results suggested that aspirin combined with vinorelbine could synergistically inhibit the proliferation of H460 cells by inducing the cell apoptosis through the mitochondrial pathway.

Preparation and evaluation of novel purine derivative F7 thermosensitive liposome / 国际药学研究杂志

Objective To prepare F7 thermosensitive liposome and evaluate its physicochemical properties, then investigate its cytotoxicity against tumor cells in vitro. Methods The F7 thermosensitive liposome was prepared by the pH gradient active drug loading method using dipalmitoyl phosphatidylcholine myristoyl lyso-phosphocholine and 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine-N-methoxy (polyethylene glycol)-2000 as membrane materials. The encapsulation efficiency and drug loading were determined for the F7 thermosensitive liposome by HPLC. The phase transition temperature of F7 thermosensitive liposome was investigated by differential scanning calorimetry;the liposome morphology was observed by atomic force microscopy;the drug release of liposome was examined by dialysis;and the particle size and zeta potential were measured through Malvern particle size analyzer. The cytotoxicity of F7 and F7 thermosensitive liposome was determined by the MTT method, and the freeze-drying process was optimized using the designexpert software. Results The encapsulation efficiency of F7 thermosensitive liposomes was (97.56±0.22) ％, and the drug loading ratio was (1.51±0.01) ％. The phase transition temperature of F7 thermosensitive liposome was 39.9℃, the zeta potential was (-15.10±0.85) mV, the particle size was (86.94±1.21) nm, and the poly disperse coefficient was 0.17±0.01. Compared with the F7 injection, the F7 thermosensitive liposomes showed a stronger, dose-dependent inhibitory effect on the growth of lung cancer H1299 and breast cancer MCF-7 cells. The freeze-dried powder of liposomes dissolved well with the encapsulation efficiency of 95％ and the particle size of approximately 130 nm. Conclusion The F7 thermosensitive liposome prepared by the pH gradient active drug loading method has high encapsulation efficiency and good stability. The preparation method is simple and feasible for further development of the F7 preparation.